Investment Objective/Strategy -The First Trust Mega Cap AlphaDEX Fund is an exchange-traded fund. The investment objective of the Fund is to seek investment results that correspond generally to the price and yield, before the Fund's fees and expenses, of an equity index called the NASDAQ AlphaDEX® Mega Cap Index.

There can be no assurance that the Fund's investment objectives will be achieved.

The NASDAQ AlphaDEX® Mega Cap Index is an “enhanced” index created and administered by Nasdaq, Inc. (“Nasdaq”) which employs the AlphaDEX® stock selection methodology to select stocks from the NASDAQ US 500 Large Cap Index that meet certain criteria.

The top 100 largest stocks by market capitalization from the previous step are selected.

Remaining stocks are ranked on growth factors including 3-, 6- and 12- month price appreciation, sales to price and one year sales growth, and separately on value factors including book value to price, cash flow to price and return on assets. All stocks are ranked on the sum of ranks for the growth factors and, separately, all stocks are ranked on the sum of ranks for the value factors. A stock must have data for all growth and/or value factors to receive a rank for that style.

Each stock receives either its growth or value score from the previous step as its selection score. Selection score is determined by the “best of” growth or value rank.

The top 50 stocks based on the selection score determined in the previous step comprise the “selected stocks”. The selected stocks are divided into quintiles based on their rankings and the top ranked quintiles receive a higher weight within the index. The stocks are equally-weighted within each quintile.

The index is reconstituted and rebalanced quarterly.

Fund Overview

Ticker

FMK

Fund Type

Mega Cap

Investment Advisor

First Trust Advisors L.P.

Investor Servicing Agent

BNY Mellon Investment Servicing (US) Inc.

CUSIP

33737M508

ISIN

US33737M5085

Intraday NAV

FMKIV

Fiscal Year-End

07/31

Exchange

Nasdaq

Inception

5/11/2011

Inception Price

$19.67

Inception NAV

$19.67

Rebalance Frequency

Quarterly

Expense Ratio

0.70%

Current Fund Data (as of 3/16/2018)

Closing NAV1

$34.69

Closing Share Price2

$34.59

Bid/Ask Midpoint

$34.69

Bid/Ask Discount

0.02%

Total Net Assets

$17,345,891

Outstanding Shares

500,002

Daily Volume

680

Average 30-Day Daily Volume

2,109

Closing Share Price 52-Week High/Low

$36.81 / $28.61

Closing NAV 52-Week High/Low

$36.83 / $28.50

Number of Holdings

50

Fund Characteristics (as of 2/28/2018)7

Maximum Market Cap.

$903,783

Median Market Cap.

$121,098

Minimum Market Cap.

$52,745

Price/Earnings

19.90

Price/Book

3.22

Price/Cash Flow

12.93

Price/Sales

1.57

Top Holdings (as of 3/16/2018)

Holding

Percent

Amazon.com, Inc.

4.34%

Gilead Sciences, Inc.

3.59%

Intel Corporation

3.58%

Adobe Systems Incorporated

3.32%

Anthem, Inc.

3.27%

Caterpillar Inc.

3.21%

AT&T Inc.

3.07%

Lowe's Companies, Inc.

3.02%

General Motors Company

2.99%

CVS Health Corporation

2.92%

Holdings are subject to change.

NAV History (Since Inception)

Past performance is not indicative of future results.

Distribution Information

Dividend per Share Amt (as of 3/19/2018)3

$0.1218

30-Day SEC Yield (as of 2/28/2018)4

1.44%

12-Month Distribution Rate (as of 2/28/2018)5

1.11%

Index Yield (as of 2/28/2018)6

2.10%

Bid/Ask Midpoint vs. NAV (as of 12/31/2017)

Number of Days Bid/Ask Midpoint Above NAV

Quarter Ended

0-49Basis Points

50-99Basis Points

100-199Basis Points

>=200Basis Points

12/31/2017

21

0

0

0

9/30/2017

3

0

0

0

6/30/2017

27

0

0

0

3/31/2017

24

0

0

0

Number of Days Bid/Ask Midpoint Below NAV

Quarter Ended

0-49Basis Points

50-99Basis Points

100-199Basis Points

>=200Basis Points

12/31/2017

42

0

0

0

9/30/2017

60

0

0

0

6/30/2017

36

0

0

0

3/31/2017

38

0

0

0

The price used to calculate market return is determined by using the midpoint between the highest bid and the lowest offer on the stock exchange, on which shares of the Fund are listed for trading, as of the time that the Fund's NAV is calculated.

Top Sector Exposure (as of 3/16/2018)

Information Technology

22.08%

Consumer Discretionary

18.05%

Health Care

16.35%

Consumer Staples

11.24%

Industrials

9.81%

Financials

9.60%

Energy

6.00%

Utilities

3.80%

Telecommunication Services

3.07%

Month End Performance (as of 2/28/2018)

3 Mos

YTD

1 Year

3 Year

5 Year

10 Year

SinceFundInception8

Fund Performance *

Net Asset Value (NAV)

3.74%

2.90%

17.28%

9.75%

12.87%

N/A

9.99%

After Tax Held

3.58%

2.90%

16.66%

9.04%

12.20%

N/A

9.40%

After Tax Sold

2.20%

1.72%

10.16%

7.20%

9.93%

N/A

7.71%

Market Price

3.77%

2.81%

17.28%

9.76%

12.87%

N/A

9.99%

Index Performance **

Nasdaq AlphaDEX® Mega Cap Index

3.91%

3.00%

18.14%

N/A

N/A

N/A

N/A

Nasdaq US 500 Large Cap Index

3.07%

1.85%

17.14%

N/A

N/A

N/A

N/A

S&P 100 Index

3.41%

1.98%

17.33%

11.59%

14.54%

N/A

13.43%

Quarter End Performance (as of 12/29/2017)

3 Mos

YTD

1 Year

3 Year

5 Year

10 Year

SinceFundInception8

Fund Performance *

Net Asset Value (NAV)

5.60%

20.85%

20.85%

9.26%

13.40%

N/A

9.77%

After Tax Held

5.44%

20.21%

20.21%

8.56%

12.73%

N/A

9.17%

After Tax Sold

3.17%

11.77%

11.77%

6.82%

10.37%

N/A

7.51%

Market Price

5.77%

20.91%

20.91%

9.29%

13.41%

N/A

9.78%

Index Performance **

Nasdaq AlphaDEX® Mega Cap Index

5.80%

21.76%

21.76%

N/A

N/A

N/A

N/A

Nasdaq US 500 Large Cap Index

6.84%

21.99%

21.99%

N/A

N/A

N/A

N/A

S&P 100 Index

6.94%

21.96%

21.96%

11.71%

15.43%

N/A

13.44%

3-Year Statistics (as of 2/28/2018)

Standard Deviation

Alpha

Beta

Sharpe Ratio

Correlation

FMK

11.37%

-2.12

1.05

0.84

0.97

S&P 100 Index

10.48%

---

1.00

1.06

1.00

Standard Deviation is a measure of price variability (risk). Alpha is an indication of how much an investment outperforms or underperforms
on a risk-adjusted basis relative to its benchmark.Beta is a measure of price variability relative to the market. Sharpe Ratio is a measure
of excess reward per unit of volatility. Correlation is a measure of the similarity of performance.

*Performance data quoted represents past performance. Past performance is not a guarantee of future
results and current performance may be higher or lower than performance quoted. Investment returns
and principal value will fluctuate and shares when sold or redeemed, may be worth more or less than
their original cost.

After Tax Held returns represent return after taxes on distributions. Assumes shares have not been sold.
After Tax Sold returns represent the return after taxes on distributions and the sale of fund shares. Returns
do not represent the returns you would receive if you traded shares at other times. Market Price returns are
based on the midpoint of the bid/ask spread on the stock exchange on which shares of the fund are listed for
trading as of the time that the fund’s NAV is calculated. Returns are average annualized total returns, except
those for periods of less than one year, which are cumulative.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and
do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax
situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold
their fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

**Performance information for the Nasdaq AlphaDEX® Mega Cap Index is for illustrative purposes only and does not represent actual fund performance.

Indexes do not charge management fees or brokerage expenses, and no such fees or expenses were deducted from the performance shown. Indexes are unmanaged and an investor cannot invest directly in an index.

On April 8, 2016, the fund's underlying index changed from the Defined Mega Cap Index to the NASDAQ AlphaDEX® Mega Cap Index. Therefore, the fund's performance and historical returns shown for the periods prior to this date are not necessarily indicative of the performance that the fund, based on its current index, would have generated.

The expense ratio for this fund is 0.70%.

Nasdaq US 500 Large Cap Index - The Index is a float modified market capitalization weighted index that contains the top 500 securities from the NASDAQ US Benchmark Index.

S&P 100 Index - The Index is a subset of the S&P 500 Index. It is comprised of 100 U.S. stocks selected for sector balance. The stocks in the S&P 100 Index are generally among the largest and most established companies in the S&P 500 Index.

Fund shares are purchased and sold on an exchange at their share price rather than net asset value (NAV), which may cause the shares to trade at a price greater than NAV (premium) or less than NAV (discount).

3

Most recent distribution paid or declared to today's date. Subject to change in the future. There is no guarantee that the fund will declare dividends.

4

The 30-day SEC yield is calculated by dividing the net investment income per share earned during the most recent 30-day period by the maximum offering price per share on the last day of the period and includes the effects of fee waivers and expense reimbursements, if applicable.

5

12-Month Distribution Rate is calculated by dividing the sum of the fund's trailing 12-month ordinary distributions paid or declared by the NAV price. Distribution rates may vary.

6

Index yield represents the weighted average trailing 12-month dividend of the constituents of the Nasdaq AlphaDEX® Mega Cap Index.

7

All market capitalization numbers are in USD$ Millions.

8

Inception Date is 5/11/2011

You should consider the fund's investment objectives, risks, and charges and expenses carefully before investing. You can download a prospectus or summary prospectus, or contact First Trust Portfolios L.P. at 1-800-621-1675 to request a prospectus or summary prospectus which contains this and other information about the fund. The prospectus or summary prospectus should be read carefully before investing.

ETF Characteristics

The fund lists and principally trades its shares on The Nasdaq Stock Market LLC.

The fund's return may not match the return of the Nasdaq AlphaDEX® Mega Cap Index. Securities held by the fund will generally not be bought or sold in response to market fluctuations.

Investors buying or selling fund shares on the secondary market may incur customary brokerage commissions.
Market prices may differ to some degree from the net asset value of the shares. Investors who sell fund shares may receive less than the share's net
asset value. Shares may be sold throughout the day on the exchange through any brokerage account. However, unlike mutual funds, shares may only be
redeemed directly from the fund by authorized participants, in very large creation/redemption units. If the fund's authorized participants are unable
to proceed with creation/redemption orders and no other authorized participant is able to step forward to create or redeem, fund shares may trade at
a discount to the fund's net asset value and possibly face delisting.

Risk Considerations

The fund's shares will change in value, and you could lose money by investing in the fund. One of the principal risks of investing in the fund is market risk. Market risk is the risk that a particular stock owned by the fund, fund shares or stocks in general may fall in value. There can be no assurance that the fund's investment objective will be achieved.

The fund may invest in securities issued by companies concentrated in a particular sector which involves additional risks including limited diversification.

First Trust Advisors L.P. is the adviser to the fund. First Trust Advisors L.P. is an affiliate of First Trust Portfolios L.P., the fund's distributor.

The NASDAQ AlphaDEX® Mega Cap Index (the "Index") is a trademark of Nasdaq, Inc. and has been licensed for use by First Trust Portfolios L.P. AlphaDEX® is a trademark owned by First Trust Portfolios L.P. and has been licensed to Nasdaq, Inc. for use in the name of the Index. The First Trust Mega Cap AlphaDEX® Fund is not sponsored, endorsed, sold or promoted by Nasdaq, Inc. and Nasdaq, Inc. makes no representation or warranty regarding the advisability of investing in the First Trust Mega Cap AlphaDEX® Fund or as to the result to be obtained by any person from use of the Index in connection with the trading of the First Trust Mega Cap AlphaDEX® Fund.

"AlphaDEX®" is a registered trademark of First Trust Portfolios L.P. First Trust Portfolios L.P. has obtained a patent for the AlphaDEX® stock selection methodology from the United States Patent and Trademark Office.

Not FDIC Insured • Not Bank Guaranteed • May Lose Value

The information presented is not intended to constitute an investment recommendation for, or advice to, any specific person. By providing this information, First Trust is not undertaking to give advice in any fiduciary capacity within the meaning of ERISA and the Internal Revenue Code. First Trust has no knowledge of and has not been provided any information regarding any investor. Financial advisors must determine whether particular investments are appropriate for their clients. First Trust believes the financial advisor is a fiduciary, is capable of evaluating investment risks independently and is responsible for exercising independent judgment with respect to its retirement plan clients.

First Trust Portfolios L.P. Member SIPC and FINRA.
First Trust Advisors L.P.